Prepare the marinade in a saucer then coat each steak evenly and leave aside for 30 minutes.
Peel and dice the onion finely. Deseed and finely chop the chilies. Soak the tomatoes in boiling water for 1 minute. Remove to rinse under running tap water until cool. Peel and slice into thin pieces. Shred the ginger and slice the garlic.
Heat a frying pan with the oil. Saute the ginger, onion, garlic, and chilies till pungent. Slice in the fish steaks to shallow fry for 2 minutes. Add the tomato slices, sizzle the wine and pour in the water. Cover and simmer gently for 5 minutes. Season to taste and dish.